The present invention relates to liquid dispensers and more specifically relates to a precompression system for a liquid dispenser whereby liquid in a container is not discharged from the dispenser until a predetermined pressure level is reached.
Containers having dispenser assemblies secured thereto are well known. One conventional dispensing system includes a container or bottle having and opening with a removable cap. Typically, the cap is secured over the container opening by screwing the cap onto external threads formed on a neck of a bottle. The screw cap is typically formed as a separate item that is assembled from a number of components. In addition, external threads must be formed on the neck of the bottle. This requires sophisticated molds and molding techniques be used. As a result, conventional liquid dispensers have a large number of parts and assembly of the parts is complex.
Another type of liquid dispenser includes a sprayer bottle having a sprayer housing fixed onto the neck of a container. The sprayer housing generally contains a manually operated pump having a suction side and a compression side. An operating element, such as a trigger, is typically pivotally connected to the pump for operating the pump. A dip tube may extend from the suction side of the pump and into the container so that the liquid in the container may be drawn through the dip tube and into the pump during operation thereof. The trigger sprayer also includes an outlet in fluid communication with the compression side of the pump for discharging the fluid. The trigger sprayer typically includes a spring located in the pump for biasing the piston of the pump to return to a charged position at the end of a discharging pump stroke.
Most trigger sprayers are connected to containers by providing the sprayer with an internally threaded ring and forming external screw threads on the container, preferably at a neck portion of the container. As such, the trigger sprayer is assembled with the container by screwing the trigger sprayer onto the external threads of the container. The need for forming internal and/or external threads adds significant cost to the manufacture and assembly of such dispensers. Manufacturing costs are typically increased because more complicated molding techniques and molds must be used to form threads in the molded components. Assembly costs are increased because sophisticated equipment and/or additional personnel must be used to screw the trigger sprayer onto the external threads of the container.
Thus, the present invention provides a method of making a liquid dispenser that has many advantages over conventional methods. In conventional methods, the container or bottle is typically formed at a first location such as by means of blow molding, and is then fed to a filling line. The bottle typically includes a fixing means such as screw threads provided in the vicinity of the bottle opening or a neck portion thereof. A filling head which is typically assembled at another location is then screwed on to the external threads provided on the neck of the bottle. At the filling line, the bottle is filled and the cap is screwed onto the external threads. This conventional method of filling and assembling bottles requires a relatively large number of operations that are not well integrated with one another so that the assembly process is both time consuming and expensive. In addition, all of the component parts for the final assembly must be formed well before final assembly of the container which results in high inventory costs. Moreover, once the containers have been formed, the empty containers take up a relatively large amount of space during transport to a filling station.
Prior art dispensing devices of the type described above generally have a high number of parts resulting in a product that is both difficult to manufacture and assemble. As a result, both the manufacturing and the assembly of the dispenser parts are expensive and time consuming. This expense and time factor is multiplied by the wide variety of trigger sprayers and containers that are commonly produced. In addition, the various trigger sprayers are often made of different materials, thereby posing problems in handling and recycling the trigger sprayer and the container when the items are ready to be discarded. For example, most, if not all, prior art trigger sprayers employ a metal spring in the pump chamber for returning the trigger to a charged position. As a result, the metal spring must be removed from the trigger sprayer before the plastic portion of the item may be recycled.
Another problem noted with conventional dispensers is that they are ill suited for dispensing consistent doses of fluid each time they are actuated. In response to this problem, commonly assigned U.S. Pat. No. 5,730,335 discloses a precompression system for a dispensing device that prevents liquid from leaving a discharge nozzle of the dispenser at too low a pressure, which would result in insufficient atomization of the liquid with large drops of fluid or liquid being formed in the spray pattern. The precompression system includes a precompression valve moveable between a position that closes off communication between a pump chamber and a discharge nozzle and an open position in which it is spaced from a valve seat for opening communication between the pump chamber and the discharge nozzle. The precompression valve is biased toward a closed position by a spring element. The precompression valve is moved to its open position only when a predetermined pressure is attained within the pump chamber.
One known problem associated with certain precompression systems is that the valve is arranged in line with the pump chamber. Therefore, it is difficult to design this type of precompression system using injection-molding processes. Furthermore, because the valve is in line with the pump chamber of the dispenser housing, the resulting design is relatively bulky, making it difficult to incorporate the precompression feature into compact dispenser housing assemblies and making assembly of such devices complex, costly and time-consuming.
The present invention relates to various types of liquid dispensers and assembly methods for making such dispensers that overcome the problems described above.
In certain preferred embodiments of the present invention, a liquid dispenser includes a dispenser subassembly having an inlet, an outlet, and a pump in fluid communication with the inlet and the outlet, the pump being movable between a first position and a second position. The liquid dispenser also preferably includes a container having an opening and an actuating clement connected thereto. The actuating element is desirably engagable with the dispenser subassembly when the container and the dispenser subassembly are assembled together. In certain preferred embodiments, engagement of the actuating element with the dispenser subassembly is a prerequisite for operating the pump and dispensing the liquid from the dispenser.
The actuating element is preferably connected to the container adjacent the opening of the container, such as being integrally connected to or integrally molded to the container. The container and the actuating element may be made of a polymer, such as a resilient thermoplastic material. The actuating element may include a biasing element, such as one or more flexible springs, engagable with the dispenser subassembly for urging the pump of the subassembly into one of the first and/or second pump positions. In certain embodiments, the container has a longitudinal axis and the biasing element extends in a direction substantially parallel to the longitudinal axis. In these embodiments, the biasing element includes two legs having first ends connected to the container and second ends remote therefrom, the legs having intermediate sections extending away from the opening of the container and the second ends of the legs including a curved portion, such as an inverted U-shaped section. The two legs of the biasing element may be substantially parallel to one another. In still other preferred embodiments, the biasing element extends in a direction substantially perpendicular to the longitudinal axis, such as one or more flexion springs connected to the container.
The container of the present invention preferably has an opening for receiving a liquid, such as a cleaning solution or a high viscosity gel. The container is preferably a thermoplastic preform that is fabricated using injection-molding techniques. The preform may be blow molded into a container having a desired shape immediately before the container in filled with a liquid and assembled with one of the dispenser subassemblies of the present invention. The container desirably includes a shroud extending away from and at least partially surrounding the opening. The shroud is desirably engagable with the dispenser subassembly when the dispenser subassembly and the container are assembled together. The shroud preferably has an inner dimension or shape that substantially coincides with the outer dimension of the dispenser subassembly and/or the housing. The shroud may include an exterior surface having a grippable surface that is sized and shaped to fit a user""s hand when a user desires to use the liquid dispenser of the present invention. The shroud preferably includes an interior surface that may surround the biasing element connected to the container and/or the container opening. The interior surface of the shroud, as will be described in more detail below, also includes at least one element that is essential for operating the dispenser subassembly for discharging liquid from the dispenser. As such, either the interior surface or the exterior surface of the shroud, or both, may serve as the actuating element for the dispenser of the present invention. As used herein, the term actuating element means a part that cooperates with or engages the dispenser subassembly for operating the subassembly and the liquid dispenser. The liquid dispenser will generally not operate unless the actuating clement engages the dispenser subassembly.
In certain embodiments, the shroud includes a lower end integrally connected with the container adjacent the opening and an upper end remote therefrom. The shroud may also include a front section, a rear section and two side sections extending between the front and the rear. The front of the shroud may be adjacent the biasing element and the rear of the shroud remote therefrom. The sides of the shroud may include one or more slots extending between the interior surface and the exterior surface of the shroud. The slots are sized to receive one or more tabs extending from the housing so that the housing may be snap-fit into the shroud during assembly of the container and the dispenser subassembly.
In highly preferred embodiments, neither the dispenser subassembly nor the container have threads and the dispenser subassembly is not screwed onto the container. As a result, molding techniques for making the component parts may be greatly simplified and there is no need for sophisticated molding devices typically used to form threads in molded parts. This results in a dramatic savings in manufacturing costs. In addition, assembly of the liquid dispenser is simpler because the dispenser subassembly is not screwed onto the container. This greatly reduces assembly costs.
In certain preferred embodiments, the dispenser subassembly includes a housing, preferably made on a thermoplastic material, having the inlet for drawing the liquid into the housing and the outlet for discharging the liquid from the housing. The housing may also have a front, a rear, two lateral sides extending between the front and the rear, an upper end and a lower end. The lower end of the housing generally has a base, such as a circular base, sized and adapted for being secured within the opening of the container. The base may be substantially circular and include an opening for the inlet for liquid into the housing. The housing desirably includes the pump comprising a pump chamber having a first open end facing the front of the housing, a second substantially closed end remote therefrom, and an interior wall extending between the first and second ends thereof. The interior wall has substantially cylindrical shape when viewed in cross-section. The pump also includes a piston movable between the first and the second ends of the pump chamber. The piston may include a piston rod having first and second annular sealing elements adapted for engaging the interior wall of the pump chamber.
The housing of the dispenser subassembly may include one or more peripheral tabs and, as mentioned above, the shroud includes one or more slots sized to receive the tabs so that the dispenser subassembly may be reliably secured to the shroud and the container. The housing may also include a top having a substantially flat upper surface that is adapted for receiving indicia, such as writing or a label indicating the type of liquid and/or product stored in the container. The flat upper is surface of the container preferably comprises the uppermost portion of the container. The flat upper surface may facilitate stacking of multiple containers atop one another during shipping or storage. In other embodiments, the top of the dispenser subassembly lies in substantially the same plane as the upper edge of the shroud.
A movable element or member may be connected to the piston for moving the piston between the first and second ends of the pump chamber, whereby the actuating member engages the movable member when the dispenser subassembly and the container are assembled together for urging the movable member and the piston toward the first pump position. In certain embodiments, the movable member includes a trigger having an upper end, a lower end and a mid-section between the upper and lower ends. The upper end of the trigger may be hingedly connected to the housing while the mid-section of the trigger may be pivotally connected to the piston. The trigger preferably includes an aperture between the mid-section and the upper end thereof, whereby the outlet of the housing, and any nozzle rotatably secured to outlet, may extend through the trigger aperture when the trigger is connected to the housing. The trigger may have a rear surface with one or more channels formed therein for engaging the actuating element during assembly of the liquid dispenser with the container, whereby the actuating element urges the trigger and the piston pivotally connected therewith toward the first pump position. The nozzle may be rotated for changing the shape of a spray discharged from the liquid dispenser and/or for locking the dispenser from dispensing any liquid whatsoever.
In other preferred embodiments of the present invention, a precompression system for a liquid dispenser is operable for allowing liquid entering the inlet to reach the outlet only after a predetermined pressure is established in the pump chamber. The precompression system stops the liquid from reaching the outlet when the pressure in the pump chamber falls below the predetermined pressure. The precompression system preferably includes a valve chamber formed in the housing having a first end facing the rear of the housing, a second end remote therefrom, and an interior wall extending between the first and second ends thereof. The second end of the valve chamber desirably includes an end wall having a valve seat and an is opening extending through the center of the valve seat. The end wall at the second end of the valve chamber also preferably includes at least one relatively small opening therein that extends to the pump chamber for providing fluid communication between the pump chamber and the valve chamber.
The precompression system may include a spring valve having a first end including a flexible diaphragm engagable with the valve seat, a second end remote therefrom and an exterior sleeve extending between the first and second ends. The exterior sleeve of the valve is preferably engagable with the interior wall of the valve chamber. The flexible diaphragm at the first end of the valve preferably includes a convex surface facing the valve seat and a concave surface facing away from the valve seat. The flexible diaphragm, and particularly the convex face thereof, is engagable with the valve seat and normally closes the opening in the valve seat. The diaphragm is preferably in substantial alignment with the outlet of the housing. In embodiments where the container includes a shroud, it is desirable that an interior surface of the shroud engage the dispenser subassembly when the dispenser subassembly and the container are assembled together so that the interior surface of the shroud, and preferably a substantially flat surface connected and/or integrally molded with the shroud, may engage and/or contact the second end of the spring valve for securing the spring valve within the valve chamber. The flat surface in contact with the second end of the valve prevents the spring valve from backing out of the valve chamber during operation of the dispenser. The dispenser would not operate without the inner surface of the shroud engaging the valve.
The housing may include a liquid supply opening between the inlet and the pump chamber that supplies fluid communication there between. In these embodiments, the liquid supply opening extends through the interior wall of the valve chamber and the spring valve includes the exterior sleeve engaging the interior wall of the valve chamber for affecting the flow of the liquid into the pump chamber. The spring valve may include a peripheral flap projecting from the first end of the valve, wherein the peripheral flap covers the liquid supply opening between the liquid inlet and the pump chamber. The peripheral flap may be flexible and incline toward the interior wall of the valve chamber. The peripheral flap preferably seals the liquid supply opening when the piston moves from the first charged position to the second discharged position and opens the liquid supply opening when the piston moves from the second position to the first position. In other words, the peripheral flap is movable away from the liquid supply opening when the piston moves from the second position to the first position so that the liquid may be drawn into the pump chamber and engages the interior wall of the valve chamber during a discharge stroke
When the spring valve is seated in the valve chamber, the flexible diaphragm of the spring valve preferably has a convex face in contact with the valve seat and in fluid communication with the pump chamber, whereby the convex face is forced away from the seat valve opening when the pressure within the pump chamber is greater than the combined force of the diaphragm and the ambient pressure cavity. The diaphragm is preferably dome-shaped and may includes a stop member integrally forced with the diaphragm on the concave face or surface thereof. The stop member prevents the diaphragm from flexing too far toward the second end of the valve that the diaphragm becomes invented.
The precompression system of the present invention provides many advantages over conventional liquid dispensers, such as trigger sprayers. With a standard trigger sprayer, as the pressure is building up or decreasing, there will be drips in the pattern that is being sprayed from the trigger sprayer at the beginning of the stroke and near the end of the stroke. When using a precompression valve in accordance with preferred embodiments of the present invention, there is no flow and no drips at the start of the stroke and, when the valve assembly opens, there is a sufficiently high pressure so that there is no immediate spray pattern from the outlet orifice in the nozzle until the pressure in the pumping chamber decreases to a predetermined value where the precompression valve assembly closes and again there is no flow or drips from that point to the end of the stroke of the piston. On release of the trigger and while the piston is moving under the force of the spring to its at rest position during the return stroke of the piston, the valve assembly is closed and there is no flow or drips.
In other embodiments, the liquid dispenser is designed for dispensing specific doses or metered amounts of a liquid, such as a liquid soap or gel. In these embodiments, the housing of the dispenser subassembly includes the pump chamber and a vent chamber adjacent the pump chamber. The liquid dispenser includes a movable element having a first piston and a second piston integrally connected thereto, wherein the first piston has an outer dimension sized for closely engaging an internal wall of the pump chamber and the second piston has an outer dimension sized for closely engaging an internal wall of the vent chamber. The movable element is movable between a first position and a second position, wherein the movable member is closer to the container in the second position than in the first position. The dispenser may also include a locking element cooperating with the movable element for blocking movement of the movable element toward the second pump position. The locking element may include a frangible tongue connected with the liquid outlet and/or a cover for selectively closing the outlet.
During operation, the liquid dispenser of the present invention is preferably in a charged or primed state when the piston is at the first end of the pump chamber and in a discharged or expended state when the piston is at the second end of the pump chamber. When the liquid dispenser is connected to a container, the liquid is preferably drawn into the pump chamber when the piston moves from the second position to the first position and is preferably discharged from the pump chamber when the piston moves from the first position to the second position.
In further preferred embodiments, the pump chamber has a central axis located between the inlet and the outlet. The housing also desirably includes a valve chamber between the pump chamber and the outlet, whereby the valve chamber has a central axis and is in fluid communication with the pump chamber. Although the central axes of the pump chamber and the valve chamber are substantially parallel to one another, the two chambers are not in linear alignment with one another. In other words, the central axis of the pump chamber is offset from the central axis of the valve chamber.
In still other preferred embodiments, a liquid dispenser includes a dispenser subassembly and a container subassembly assembled therewith, whereby the container subassembly includes integral therewith a portion of the housing of the dispenser subassembly. In other words, the container subassembly is adapted to cooperate with and form at least a portion of the housing for the dispenser subassembly when the dispenser subassembly and container subassembly are assembled together. In these embodiments, the actuating element may be connected with the dispenser subassembly before the dispenser subassembly and the container are connected together. As a result, the actuating element is not preassembled with the container before the dispenser subassembly and the container are assembled together. However, in other preferred embodiments, the actuating element may be connected to the container so that the actuating element is engagable with the dispenser subassembly when the container subassembly and the dispenser subassembly are in their assembled configuration.
The present invention also includes a method of priming or charging a liquid dispenser during final assembly thereof including providing a dispenser subassembly having an inlet, an outlet, and a pump in fluid communication with the inlet and the outlet, the pump being movable between a first position and a second position, and then providing a container having an opening for receiving a liquid and an actuating element connected thereto, the actuating clement being engagable with the dispenser subassembly when the dispenser subassembly and the container are assembled together. The pump of the dispenser subassembly is then positioned in the second position. The container may then be formed, filled with a liquid and assembled with the dispenser subassembly. During the final assembling step, the actuating element connected to the container engages the dispenser subassembly for moving the pump into the first pump position so as to draw the liquid into the pump. The dispenser subassembly preferably includes a movable element in contact with the pump for moving the pump between the first and second pump positions, wherein the actuating element engages the movable element during the assembly step for moving the pump from the second pump position to the first pump position.